Steam generator sludge lancing apparatus

Abstract

Apparatus for removing sludge that may be deposited on a tubesheet of a steam generator comprises fluid headers at the elevation of the sludge to be removed for establishing a circumferential fluid stream at that elevation. A fluid lance is also provided for being moved along the line between the headers emitting a pulsating fluid jet perpendicular to a line of movement of the fluid lance at an elevation substantially corresponding to the level of sludge deposits. The fluid jet forces the sludge to the periphery of the tubesheet where the sludge is entrained in and carried away by the circumferential fluid stream.

We claim as our invention: 
     
       1. Apparatus for removing sludge deposits from steam generators comprising: a mounting plate capable of being attached to said steam generator;   a first tubular member having a plurality of outlet openings therein attached to said mounting plate and capable of being disposed through an opening in said steam generator;   a second tubular member disposed within said first tubular member defining a first annular chamber therebetween for conducting a first fluid to said outlet openings for establishing a peripheral flow within said steam generator;   a third tubular member having a first bore therein slidably disposed within said second tubular member for conducting a pulsating second fluid to said sludge deposits;   a head mounted on the end of said third tubular member for directing said second fluid toward said sludge deposits thereby carrying said sludge deposits to said peripheral flow; and   at least two nozzles mounted on said head between approximately 20° to 30° from the horizontal for emitting said pulsating second fluid.   
     
     
       2. The apparatus according to claim 1 wherein said head has a top hole therein for emitting a pulsating flow to balance the forces on said head. 
     
     
       3. The apparatus according to claim 2 wherein said nozzles are mounted on said head at an angle of approximately 25° from the horizontal. 
     
     
       4. The apparatus according to claim 3 wherein said outlet openings are arranged in said first tubular member between approximately 14° to 16° from the horizontal. 
     
     
       5. The apparatus according to claim 4 wherein each of said nozzles has a conical chamber leading to a rectangular outlet channel. 
     
     
       6. The apparatus according to claim 5 wherein said outlet channel has a length of at least 0.25 inch. 
     
     
       7. The apparatus according to claim 6 wherein each of said nozzles has an outer rectangular opening of approximately 0.25 inch by 0.094 inches. 
     
     
       8. The apparatus according to claim 7 wherein said top hole has a diameter of approximately 11/64 inches. 
     
     
       9. The apparatus according to claim 8 wherein said outlet openings are arranged at 15° from the horizontal. 
     
     
       10. The apparatus according to claim 9 wherein said third tubular member has a rack attached thereto for sliding said third tubular member through said second tubular member. 
     
     
       11. The apparatus according to claim 10 wherein said apparatus further comprises drive means connected to said rack for moving said third tubular member.